The present invention relates to a combined microwave and electric heating oven and, more particularly, to a cooking operation control system for the combined microwave and electric heating oven.
A combined microwave and electric heating oven has been developed, which includes a magnetron for microwave cooking purposes and an electric heater for electric heating cooking purposes. However, such a magnetron and an electric heater can not be energized at a same time due to power capacity limitations. For a particular kind of menu, for example, stew, it is preferable that the microwave cooking is first conducted and, then, the electric heating cooking is performed. For another kind of menu, for example, cookies, it is preferable that the electric heating cooking is first conducted and, then, the microwave cooking is performed.
On the other hand, various sensors have been developed for automatic cooking control purposes. A microwave oven is proposed in my copending application Ser. No. 71,179, "COOKING UTENSIL CONTROLLED BY GAS SENSOR OUTPUT", filed on Aug. 31, 1979, now U.S. Pat. No. 4,311,895 wherein a gas sensor is disposed in an exhaustion duct for detecting a gas concentration developed from an oven cavity. When the gas concentration reaches a preselected value, the gas sensor output shows a preselected value, and in response thereto the microwave generation is terminated. And, a thermistor is well known for detecting a cooking temperature.
Accordingly, an object of the present invention is to provide an automatic cooking operation control system for a combined microwave and electric heating oven.
Another object of the present invention is to provide a cooking operation system which selectively responds to a gas sensor output and a thermistor output in a combined microwave and electric heating oven.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, a gas sensor is disposed in an exhaustion duct for detecting the concentration of gas developed from an oven cavity, and a thermistor is disposed in the oven cavity for detecting the ambience air temperature within the oven cavity. When, for example, the stew menu is selected by the operator, the microwave cooking is first conducted, wherein the magnetron is deenergized when the gas sensor output shows a preselected value. After completion of the microwave cooking, the electric heating cooking is performed for a preselected period of time, wherein the electric heater is intermittently energized in response to the thermistor output signal.